From the University of Colorado, Division of Cardiology, Aurora, CO (R.G.A., W.H.S., M.R.B.); ARCA biopharma, Inc, Broomfield, CO (A.D.R., M.R.B.); and University of South Florida Morsani College of Medicine, Tampa, FL (S.B.L.).

From the University of Colorado, Division of Cardiology, Aurora, CO (R.G.A., W.H.S., M.R.B.); ARCA biopharma, Inc, Broomfield, CO (A.D.R., M.R.B.); and University of South Florida Morsani College of Medicine, Tampa, FL (S.B.L.).

From the University of Colorado, Division of Cardiology, Aurora, CO (R.G.A., W.H.S., M.R.B.); ARCA biopharma, Inc, Broomfield, CO (A.D.R., M.R.B.); and University of South Florida Morsani College of Medicine, Tampa, FL (S.B.L.).

From the University of Colorado, Division of Cardiology, Aurora, CO (R.G.A., W.H.S., M.R.B.); ARCA biopharma, Inc, Broomfield, CO (A.D.R., M.R.B.); and University of South Florida Morsani College of Medicine, Tampa, FL (S.B.L.).

From the University of Colorado, Division of Cardiology, Aurora, CO (R.G.A., W.H.S., M.R.B.); ARCA biopharma, Inc, Broomfield, CO (A.D.R., M.R.B.); and University of South Florida Morsani College of Medicine, Tampa, FL (S.B.L.).

Conclusions—Bucindolol prevents VT/VF in subjects with heart failure and reduced left ventricular ejection fractions, and this effect is modulated by β1389 Arg/Gly and α2c322-325 Wt/deletion adrenergic receptor polymorphisms.